关于DES 过程密钥和密钥分散

Question

目前要做个项目 涉及到过程密钥及密钥分散，我想问下过程密钥、密钥分散的含义分别是什么，请举例说明

Answer 1

http://www.51testing.com/?uid-205133-action-viewspace-itemid-176742
http://hzhlu.iteye.com/blog/830670

Answer 2

 public class GF_Encrypt
    {
        /// <summary>
        /// DES加密
        /// </summary>
        /// <param name="pToEncrypt">加密字符串</param>
        /// <param name="sKey">密钥</param>
        /// <returns></returns>
        public static string string_Encrypt(string pToEncrypt, string sKey)
        {
            if (pToEncrypt == "") return "";
            if (sKey.Length < 8) sKey = sKey + "xuE29xWp";
            if (sKey.Length > 8) sKey = sKey.Substring(0, 8);
            DESCryptoServiceProvider des = new DESCryptoServiceProvider();
            //把字符串放到byte数组中  
            //原来使用的UTF8编码，我改成Unicode编码了，不行  
            byte[] inputByteArray = Encoding.Default.GetBytes(pToEncrypt);
            //建立加密对象的密钥和偏移量  
            //原文使用ASCIIEncoding.ASCII方法的GetBytes方法  
            //使得输入密码必须输入英文文本  
            des.Key = ASCIIEncoding.Default.GetBytes(sKey);
            des.IV = ASCIIEncoding.Default.GetBytes(sKey);
            MemoryStream ms = new MemoryStream();
            CryptoStream cs = new CryptoStream(ms, des.CreateEncryptor(), CryptoStreamMode.Write);
            //Write  the  byte  array  into  the  crypto  stream  
            //(It  will  end  up  in  the  memory  stream)  
            cs.Write(inputByteArray, 0, inputByteArray.Length);
            cs.FlushFinalBlock();
            //Get  the  data  back  from  the  memory  stream,  and  into  a  string  
            StringBuilder ret = new StringBuilder();
            foreach (byte b in ms.ToArray())
            {
                //Format  as  hex  
                ret.AppendFormat("{0:X2}", b);
            }
            ret.ToString();
            return ret.ToString();
        }        /// <summary>
        /// DES解密
        /// </summary>
        /// <param name="pToDecrypt">解密字符串</param>
        /// <param name="sKey">解密密钥</param>
        /// <param name="outstr">返回值</param>
        /// <returns></returns> 
        public static bool string_Decrypt(string pToDecrypt, string sKey, out string outstr)
        {
            if (pToDecrypt == "")
            {
                outstr = "";
                return true;
            };
            if (sKey.Length < 8) sKey = sKey + "xuE29xWp";
            if (sKey.Length > 8) sKey = sKey.Substring(0, 8);
            try
            {
                DESCryptoServiceProvider des = new DESCryptoServiceProvider();
                //Put  the  input  string  into  the  byte  array  
                byte[] inputByteArray = new byte[pToDecrypt.Length / 2];
                for (int x = 0; x < pToDecrypt.Length / 2; x++)
                {
                    int i = (Convert.ToInt32(pToDecrypt.Substring(x * 2, 2), 16));
                    inputByteArray[x] = (byte)i;
                }
                //建立加密对象的密钥和偏移量，此值重要，不能修改  
                des.Key = ASCIIEncoding.Default.GetBytes(sKey);
                des.IV = ASCIIEncoding.Default.GetBytes(sKey);
                MemoryStream ms = new MemoryStream();
                CryptoStream cs = new CryptoStream(ms, des.CreateDecryptor(), CryptoStreamMode.Write);
                //Flush  the  data  through  the  crypto  stream  into  the  memory  stream  
                cs.Write(inputByteArray, 0, inputByteArray.Length);
                cs.FlushFinalBlock();
                //Get  the  decrypted  data  back  from  the  memory  stream  
                //建立StringBuild对象，CreateDecrypt使用的是流对象，必须把解密后的文本变成流对象  
                StringBuilder ret = new StringBuilder();
                outstr = System.Text.Encoding.Default.GetString(ms.ToArray());
                return true;
            }
            catch
            {
                outstr = "";
                return false;
            }
        }

Answer 3

  public class DES
        {
            //默认密钥向量
            private static byte[] Keys = { 0x12, 0x34, 0x56, 0x78, 0x90, 0xAB, 0xCD, 0xEF };            /// <summary>
            /// DES加密字符串
            /// </summary>
            /// <param name="encryptString">待加密的字符串</param>
            /// <param name="encryptKey">加密密钥,要求为8位</param>
            /// <returns>加密成功返回加密后的字符串,失败返回源串</returns>
            public static string Encode(string encryptString, string encryptKey)
            {
                encryptKey = GF_GET.GetSubString(encryptKey, 8, "");
                encryptKey = encryptKey.PadRight(8, ' ');
                byte[] rgbKey = Encoding.UTF8.GetBytes(encryptKey.Substring(0, 8));
                byte[] rgbIV = Keys;
                byte[] inputByteArray = Encoding.UTF8.GetBytes(encryptString);
                DESCryptoServiceProvider dCSP = new DESCryptoServiceProvider();
                MemoryStream mStream = new MemoryStream();
                CryptoStream cStream = new CryptoStream(mStream, dCSP.CreateEncryptor(rgbKey, rgbIV), CryptoStreamMode.Write);
                cStream.Write(inputByteArray, 0, inputByteArray.Length);
                cStream.FlushFinalBlock();
                return Convert.ToBase64String(mStream.ToArray());            }            /// <summary>
            /// DES解密字符串
            /// </summary>
            /// <param name="decryptString">待解密的字符串</param>
            /// <param name="decryptKey">解密密钥,要求为8位,和加密密钥相同</param>
            /// <returns>解密成功返回解密后的字符串,失败返源串</returns>
            public static string Decode(string decryptString, string decryptKey)
            {
                try
                {
                    decryptKey = GF_GET.GetSubString(decryptKey, 8, "");
                    decryptKey = decryptKey.PadRight(8, ' ');
                    byte[] rgbKey = Encoding.UTF8.GetBytes(decryptKey);
                    byte[] rgbIV = Keys;
                    byte[] inputByteArray = Convert.FromBase64String(decryptString);
                    DESCryptoServiceProvider DCSP = new DESCryptoServiceProvider();                    MemoryStream mStream = new MemoryStream();
                    CryptoStream cStream = new CryptoStream(mStream, DCSP.CreateDecryptor(rgbKey, rgbIV), CryptoStreamMode.Write);
                    cStream.Write(inputByteArray, 0, inputByteArray.Length);
                    cStream.FlushFinalBlock();
                    return Encoding.UTF8.GetString(mStream.ToArray());
                }
                catch
                {
                    return "";
                }
            }
        }